Income Taxes (Components Of Federal And State Income Taxes Included In The Consolidated Statements Of Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Current Income Taxes [Abstract]
Federal			$ 36,746	$ 39,974
State			13,199	9,607
Deferred Income Taxes [Abstract]
Federal			13,242	50,110
State			(2,891)	21,829
Income Tax Expense	5,136	66,095	60,296	121,520
Deferred Investment Tax Credit			(208)	(218)
Total Income Taxes			60,088	121,302
Presented as Follows [Abstract]
Other Income			(208)	(218)
Income Tax Expense	$ 5,136	$ 66,095	$ 60,296	$ 121,520